The invention relates to a draw-off, take-up and winding arrangement for circular knitting machines wherein the tube of knitted material is wound around a take-up roller or beam thereby driving the latter and includes furthermore a draw-off roller arrangement.
With known arrangements of this type, the tube of knitted fabric is taken up by a set of driven take-up rollers. It has, however, been found that in practise such an arrangement frequently causes malfunctioning because the tube of knitted material cannot always be sufficiently, uniformly wound on the take-up rollers. Furthermore, when sensitive knitted material is to be wound, for example a material having an open or irregular pattern, the winding of the knitted fabric solely by means of driven take-up rollers results in a twisting between the inner layers of knitted fabric, which must absorb the winding or take-up forces, and the outer layers of such knitted fabric.
In the conventional arrangements of the afore-described type, the tube of knitted fabric is drawn off from the circular knitting machine by a pair of draw-off rollers. It is also already known to use three draw-off rollers in such an arrangement, in which two of these rollers are biased against a middle draw-off roller, and the latter is driven by means of a motor. A gear wheel is mounted on the spindle of each draw-off roller and these gear wheels resiliently mesh with each other so that tubular knitted fabrics of different thickness can be drawn off by such an arrangement.
Furthermore, in order to obtain a uniform take-up which also protects the tubular knitted fabric there has already been proposed to utilize an endless band which is guided over a plurality of draw-off rollers and to place the tubular knitted material between this band and one of the draw-off rollers, thereby obtaining as uniform as possible a distribution of take-up forces for both adjacent layers of the tubular knitted material (see, for example, German published patent application No. 1,635,799).
It is a general object of this invention, to provide an arrangement for drawing off, taking up and winding a hose of knitted material of the aforementioned type, wherein the tube of knitted material is more delicately and more uniformly wound up as it is in the arrangements of the prior art as described hereinabove.
According to the invention this object is attained by making the winding roller a freely rotatable idle roller and having the tube of knitted material guided from the draw-off roller to the take-up roller, and after being wound around the take-up roller it is guided back to the draw-off roller and again wound around the latter and then is secured to the periphery of the take-up roller, so that the tube of knitted material wound around the take-up roller serves to drive the latter. Thus, the portion of the tube of knitted material which is wound around the take-up roller and is then guided onto the draw-off roller before being wound on the take-up roller, presses just that portion of the tube of knitted fabric which is about to be wound onto the take-up roller against the latter or layers of knitted fabric wound on the latter, whereby frictional engagement is increased and the winding is soft and more uniform. This solution is not apparent from the known take-up arrangement of published German application No. 1,635,799 because the afore-described prior art arrangement constitutes a draw-off arrangement and not a take-up arrangement and, furthermore, the arrangement of this invention does not utilize a separate, endless band for winding the fabric onto the take-up rollers, and, finally, a transposition of known features of a draw-off arrangement to a take-up arrangement would lead to a construction requiring additional elements for pressing the endless band against the take-up rollers, respectively, the knitted fabric coil and, furthermore, would require a driving of the take-up arrangement which is precisely what has been avoided by the arrangement of this invention. By means of the arrangement of this invention all synchronization problems between the take-up roller and driven draw-off rollers are avoided. The arrangement of this invention uses advantageously a construction wherein at least a pair of draw-off rollers are biased toward each other and the tube of knitted fabric passes therebetween is mounted between. An idle roller is mounted between the pair of draw-off rollers. The tube of knitted material is guided about these three rollers prior to being wound on the take-up roller. It is particularly advantageous to utilize an embodiment having three draw-off rollers which are resiliently mounted and biased against each other; one of these three draw-off rollers is an idle guide roller. The latter arrangement of the invention is particularly advantageous in ensuring that the knitted fabric is not damaged during the take-up operation.